Applied Anatomical Study Of Suprascapular Nerve

Objective:To discuss the causes of suprascapular nerve entrapment syndrome and analyze the correlations between the regional anatomical features of the nerve's course and the syndromic clinical manifestations after the data processing by observing and measuring the nerve's origin, course, branches, distribution and their relations to neighbouring structures. It can provide the anatomical basis for diagnosing and treating suprascapular nerve entrapment syndrome.Methods:20 (13 males and 7 females, 40 sides) adult cadavers antisepticised and fixed with 10% formaldehyde, which had the intact and normal scapular regions, were selected. The scapular regions of the specimens were dissected with the aid of X 5 operation microscope. The course, branches, distribution and relations of suprascapular nerve were observed and measured.Results:①The superior transverse scapular ligament was tough and its average length was 13.93±5.19 (7.02～22.84) mm, whose thickness in the middle was 2.30±0.57 (1.42～2.94) mm. The inferior transverse scapular ligament was pliable and falciform, whose mean length was 22.22±5.66 (15.46～32.74)mm and thickness in the middle was 2.27±0.40 (1.64～2.72) mm.②The length of suprascapular nerve from its origin to the suprascapular foramen was 48.07±7.27(39.16～60.28)mm and the diameter at the nerve's originating point was1.49±0.33(0.98～1.92)mm. The length of suprascapular nerve between suprascapular foramen and infrascapular foramen was19.36±3.73(15.32～26.58)mm mm.③34 cases (85%) of suprascapular nerve passed through suprascapular foramen while suprascapular blood vessels superolaterally went over superior transverse scapular ligament. 5 cases (12.5%) of suprascapular nerve, artery and vein forming neurovascular bundles traversed suprascapular formen together. 1 cases (2.5%) of suprascapular nerve and vein penetrated suprascapular formen while suprascapular artery passed over superior transverse scapular ligament.④The turning angle of suprascapular nerve at spinoglenoid notch ranged from 32.0°to 66.0°, which averaged 50.68°±8.46°(50.5°±9.06°for left side and 50.85°±7.80°for right side).⑤The suprascapular nerve was strained when the arm extended and rotated laterally, especially for its branch to infraspinatus muscle because of its turning angle at spinoglenoid notch where suprascapular nerve was firmly pulled to the medial border of infrascapular foramen.Conclusion:Suprascapular nerve is potentially entrapped in the suprascapular or infrascapular foramina, which can be caused by the thickened superior and inferior transverse scapular ligaments or narrowed suprascapular and infrascapular foramina.